From: Alan Friedman <alan@greatarrow.com>

Date: November 7, 2008 9:40:39 PM MST

To: Astro_IIDC@yahoogroups.com

Subject: Re: [Astro_IIDC] Moray

Hi Dean,

The dreaded moire pattern... it is coming from an interference between surfaces in the optical path - with the glass in front of the CCD chip most likely being one. Have you tried rotating the barlow or blocking filter or camera? Does it remain unchanged at different effective focal lengths? 

I encountered this using a Nikon D1X with my Coronado solarmax 90 years ago and I couldn't eliminate it. I have not had a problem with either of my DMK cameras, but others have. Strangely, I did notice the pattern just the other day for the first time using my DMK 41AF02 camera with a Baader FFC. I tried using a long extension tube for higher power and saw it on the screen during capture for the first time in years. The magnification was too much for the seeing so I quit for the day. Yesterday, back to my usual settings with the FFC (3.5x) and all was fine. 

I hope you are able to eliminate it. It is a nuisance to try and remove it in Photoshop.

Alan

On Nov 7, 2008, at 6:34 PM, dean_drumheller wrote:

Using DKF 31AF03.AS, I'm getting curved lines in all images and not sure how to deal with
them. I've tried many different focus, exposure and image controls and not making any
progress. Appreciate a starting point, any input on fixing the image. Thanks -Dean
Link: http://collegeofsanmateo.edu/astronomy/Image%20Post.asp